Noometry

Model comparison

GPT-5.2 Codex vs GPT-6 Luna

GPT-6 Luna is the stronger model overall, scoring 53.3 to 42.6 on the Noometry Index.

Last verified . 2 shared benchmarks.

GPT-5.2 Codex OpenAI

42.6

Rank #111 Reported

GPT-6 Luna OpenAI

53.3

Rank #36 Confirmed

Summary

  • They share 2 benchmarks with published results for both. GPT-5.2 Codex scores higher in 1 category and GPT-6 Luna in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in coding, where GPT-6 Luna leads 55.5 to 45.5.
  • GPT-6 Luna is cheaper at $0.10 / $0.50 per million input/output tokens, against $1.75 / $14 for GPT-5.2 Codex.
  • GPT-6 Luna accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5.2 CodexGPT-6 Luna
ProviderOpenAIOpenAI
Noometry Index42.653.3
Released2025-12-182026-09-22
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K128K
Input $ / M tokens$1.75$0.10
Output $ / M tokens$14$0.50
Results tracked542

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Category by category

Coding GPT-6 Luna leads

GPT-5.2 Codex: 45.5 (#71), GPT-6 Luna: 55.5 (#25)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena WebDev13391581
ALE-Bench1,3001,577
DeepSWE—66.6%
FrontierCode—42.4%
SWE-bench Verified (bash only)72.8%—
SWE-bench Multilingual66.3%—
SciCode—54.6%
LMArena Coding—1439

Agentic & Tool Use GPT-5.2 Codex leads

GPT-5.2 Codex: 41.0 (#22), GPT-6 Luna: 33.3 (#54)

BenchmarkGPT-5.2 CodexGPT-6 Luna
Terminal-Bench66.5%—
APEX-Agents—44.3%
GDP.pdf—23%

Reasoning Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 48.2 (#41)

BenchmarkGPT-5.2 CodexGPT-6 Luna
ARC-AGI-2—59.3%
NYT Connections (extended)—68.7%
ARC-AGI-1—86.7%
CritPt—19.4%
Chess Puzzles—31%
LMArena Hard Prompts—1411
Mystery Game Puzzles—7%
DTBench—90.1%
LMCA—44.5%
Epoch Capabilities Index—156.28

Math Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 76.1 (#15)

BenchmarkGPT-5.2 CodexGPT-6 Luna
FrontierMath (Tiers 1-3)—78.9%
FrontierMath Tier 4—56.1%
OTIS Mock AIME 2024-2025—98.9%
ProofBench—64%
LMArena Math—1416

Knowledge Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 57.0 (#41)

BenchmarkGPT-5.2 CodexGPT-6 Luna
GPQA Diamond—90.5%
SimpleQA Verified—41.4%
LMArena Expert—1444

Multimodal Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 42.4 (#30)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena Vision—1217
Blueprint-Bench 2—31.2%
Furniture Assembly—44.2%

Multilingual Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 50.5 (#117)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena Non-English—1386
LMArena Chinese—1433
LMArena French—1420
LMArena German—1369
LMArena Japanese—1369
LMArena Korean—1360
LMArena Russian—1394
LMArena Spanish—1393

Instruction Following Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 74.3 (#99)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena Instruction Following—1409

Long Context Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 43.0 (#111)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena Longer Query—1409

Writing & Preference Not comparable

GPT-5.2 Codex: —, GPT-6 Luna: 58.3 (#119)

BenchmarkGPT-5.2 CodexGPT-6 Luna
LMArena Text—1391
LMArena Creative Writing—1363
LMArena Multi-Turn—1396

Frequently asked questions

Is GPT-5.2 Codex better than GPT-6 Luna?

GPT-6 Luna is the stronger model overall, scoring 53.3 to 42.6 on the Noometry Index.

Which is cheaper, GPT-5.2 Codex or GPT-6 Luna?

GPT-6 Luna is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.

Is GPT-5.2 Codex or GPT-6 Luna better for coding?

GPT-6 Luna scores higher on coding benchmarks: 55.5 versus 45.5 in the Noometry coding category.

Which has the bigger context window?

GPT-6 Luna does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5.2 Codex and GPT-6 Luna share?

2 benchmarks have published results for both models. GPT-5.2 Codex has 5 scored results on Noometry and GPT-6 Luna has 42.

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